Hydraulic pressure devices are efficient at producing high torque from relatively compact units. Their ability to provide low speed and high torque make them adaptable for numerous applications. U.S. Pat. Nos. 4,285,643, 4,357,133, 4,697,997 and 5,173,043 are examples of hydraulic motors.
In these devices the input/output mechanism, typically a drive shaft with bearings and a wobblestick, develop heat and residue such as sludge (from heat) and metal powder (from wear). A number of these devices therefor incorporate lubrication circulation paths to pass fluid continually over such input/output mechanism. Examples include U.S. Pat. No. 4,533,302 (parasitically drains fluid outward off of each pressurized volume chamber), U.S. Pat. No. 4,390,329 (use naturally occurring leakage), U.S. Pat. Nos. 3,749,195 and 4,480,972 (uses inactive seals), U.S. Pat. Nos. 3,572,983 and 4,362,479 (uses ball check valves) and U.S. Pat. No. 4,285,643 (uses one of the two main fluid ports).
These prior art units, however, either require extensive machining or contaminate the hydraulic fluid prior to usage in the pressure mechanism.
The present invention eliminates these problems.